A set of temperature-controlled direct shear test apparatus for the interface of reinforced soil was developed.Eleven groups of direct shear tests were conducted to study the influence of water contents,interface temperatures,and freeze-thaw cycles on the shear behavior of the geogrid-soil interface.The results show that the cohesion and friction angle of the geogrid-soil interface both decrease with the increase of water contents,as does the shear strength at the geogrid-soil interface.The reinforcement can obviously improve the shear strength of the frozen soil.When the interface temperature is-10℃,the peak shear stress at the geogrid-soil interface increases by about 20% relative to the unreinforced soil.The reinforcement provided by the geogrid increaes as the interface temperature drops.The shear stress is higher and the shear stress-shear displacement will show the peak strength and residual strength when the interface temperature drops below 0℃,whereas in a non-frozen state,the interface exhibits lower shear stress with a consistent stable value.The shear strength of the geogrid-soil interface decreases after freeze-thawing.Furthermore,both the cohesion and friction angle of the geogrid-soil interface decrease with the increase of freeze-thaw cycles number but tend to stabilize after four freeze-thaw cycles.The research results have reference for the design and application of geogrid reinforced soil structures in permafrost and seasonal frozen regions.
维普
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